Can an MPPT Controller use an Alternator as an Input?

[Bob B]

@Wellydex ..... Thank you very much for the informative input.

 

[JamesInWa]

Am in the process of doing pretty much what the OP had in mind. To get round the voltage +5 ( or whatever the particular charger requires ) will be running a 24v alternator through the SCC into a 12v battery.

 

[Boondock Saint]

Has some limits > https://precisioncircuitsinc.com/product/battery-isolation-manager-225-amps-lithium-battery/

 

[JamesInWa]

Hi Boondock, not really sure what the relevance is , perhaps to a previous post in the above thread i missed?

 

[Boondock Saint]

Battle Born recommended this to me to charge lithium batteries while driving, from the alternator. There's a downloadable spec sheet on the website. Perhaps you can call them with question to better determine if this would benefit your situation.

The Lithium Battery Isolation
Manager (Li-BIM) isolates the two battery
systems, chassis, and coach, in a motorhome. This
prevents loads in one system from discharging both. It
also connects the two battery systems together during
charging. Both batteries are charged if either is being
charged. The coach battery is charged while driving and
the chassis battery is charged while plugged into Shore
Power at a campground.

 

[Pappion]

Battle Born recommended this to me to charge lithium batteries while driving, from the alternator. There's a downloadable spec sheet on the website. Perhaps you can call them with question to better determine if this would benefit your situation.

This does not boost voltages. You will still have float voltages.

 

[Pappion]

I built a DC-DC charger for travel trailer. Used a 15A 13.8v Boost DC-DC converter, sealed, with heat sink from China. I don't trust China.
Used 30A fuses on input and output. Also used a 15A self reset CB on the output to give the converter some cool down time.
A relay cut it off when the Tow Vechicle (7 pin plug) did not supply power.

 

[ERNWA]

Its a dc-dc charger for a reason. It takes lower voltages and ramps it up. And a charge controller takes higher voltages and lowers them.

Your alternator only outputs 14.4v before you run 10ft of wiring. Theres not enough voltage to charge. You can power an inverter and a dc power supply at 16v+ into a controller.

Then by this reasoning it would be safe if I had a 24v alternator and connected it to an MPPT charge controller for a 12v system? Just curious as I am thinking about my build.

Thanks in advance.

 

[Pierre]

Then by this reasoning it would be safe if I had a 24v alternator and connected it to an MPPT charge controller for a 12v system? Just curious as I am thinking about my build.

Thanks in advance.

Just remember that the alternator can output 60 - 80 amps at 24 volts into your MPPT controller and if your MPPT goes south you will subject your 12v system to some serious damage. You will have to somehow control / limit the alternator current output e.g. a fuse and hope it will blow fast enough.
The nice aspect of PV panels is that they are self regulating and have an Isc which cannot be exceeded and you design / select your MPPT accordingly.

 

[DJSmiley]

Adding a fuse is recommended anyway.

I think it should work fine. An alternator doesn't push 60-80A, it depends on the connected equipment what is actually pulled. A regular AC socket eg also doesn't push 15A, it only means it *can* provide 15A when requested.

I fully agree the PV is limiting the current by default. Even at the worst case of a almost fully short, the panels can't provide more amps, unlike the alternator, which can probably provide more current. (Overloading the wires, and in worst case also damaging the MPPT, depending on it's design).
I think we can agree it *might* work but it's not recommended.

 

[Pierre]

Adding a fuse is recommended anyway.

I think it should work fine. An alternator doesn't push 60-80A, it depends on the connected equipment what is actually pulled. A regular AC socket eg also doesn't push 15A, it only means it *can* provide 15A when requested.

I fully agree the PV is limiting the current by default. Even at the worst case of a almost fully short, the panels can't provide more amps, unlike the alternator, which can probably provide more current. (Overloading the wires, and in worst case also damaging the MPPT, depending on it's design).
I think we can agree it *might* work but it's not recommended.

Sorry , wrong choice of words. Most people on this forum has a basic grasp of electrics and understand what was implied. Maybe I should have said ‘can supply’ . ? I meant to say that in an electric circuit the current is directly proportional to the applied voltage and inversely proportional to the resistance of the load.

 

[Sgt Raven]

Adding a fuse is recommended anyway.

I think it should work fine. An alternator doesn't push 60-80A, it depends on the connected equipment what is actually pulled. A regular AC socket eg also doesn't push 15A, it only means it *can* provide 15A when requested.

I fully agree the PV is limiting the current by default. Even at the worst case of a almost fully short, the panels can't provide more amps, unlike the alternator, which can probably provide more current. (Overloading the wires, and in worst case also damaging the MPPT, depending on it's design).
I think we can agree it *might* work but it's not recommended.

My DC-DC/MPPT will only pull 50A total, if I understand the specs correctly. I wonder if you can set a max amperage in his charge controller?

 

[sdj]

Yes you can. Wire the stator through the rectifier diodes direct to the MPPT input, and run the voltage regulator sense wire direct to the battery.

 

[RV8R]

I posted a specific question in the all-in-one forum but didn't get any joy. Does anyone know if an MPPT SCC can act as a DC-DC converter and use an alternator as an input?

Look Up Kisae DMT 1250

 

[sdj]

Look Up Kisae DMT 1250

The Kisse unit doesn't address the problem of the alternator running hot because its burning up half of its output as heat. Learn about kirchhoff's laws.

 

[Pappion]

Then by this reasoning it would be safe if I had a 24v alternator and connected it to an MPPT charge controller for a 12v system? Just curious as I am thinking about my build.

Thanks in advance.

Danger Danger Will Robinson!
Is the MPPT controller the typical Positive Ground? Your using it with a Negative Ground source. PV panels float and not tied to ground.

 

[dzuljo]

Hello.
I am using dc/dc 12v to 19v for my laptop.
If i connect this in my cigarette lighter for source and to other side in my mppt to charge battery when i am driving i think will work.
On mppt i will reduce input amperage to protect alternator.
Is this will work ?
Thanks

 

[Solarcabin Channel]

You might be able to use a 24 volt alternator with that Victron so it reaches minimum voltage required?

 

[timselectric]

Hello.
I am using dc/dc 12v to 19v for my laptop.
If i connect this in my cigarette lighter for source and to other side in my mppt to charge battery when i am driving i think will work.
On mppt i will reduce input amperage to protect alternator.
Is this will work ?
Thanks

It's probably not the alternator that you need to protect. What's the current limit on the DC to DC converter? And the limit on the cigarette lighter outlet?
They are well below the alternator limit.

 

[mikefitz]

I am using a Chargery BMS, so I can set the min and max voltage with it and remotely shut down charge and load.

Not a good idea

running a 24v alternator through the SCC into a 12v battery.

Another bad idea.

Use the MPPT controller with solar panels.
Use a DC to DC B2B charger for alternator charging.

If the crazy ideas are, in fact, viable, then why do Victron and other manufactures bother to market B2B chargers?